Not affiliated with AHIP/CMS/Medicare; educational only, not insurance advice
Calculate a planning timeline
Planning estimate: the local plan cites the official pages below but does not include their full rule text. Detailed date boundaries have not been reverified during this offline build. Confirm your dates with SSA / Medicare before changing contributions or coverage.
Tool entries are not stored or sent; they stay in this page’s memory. Clearing or refreshing removes the displayed entries. Your browser may retain autofill information independently. A saved PDF contains your entries; keep it private. Do not enter Medicare or Social Security numbers.
Print includes entries, results, assumptions and sources. Dates use YYYY-MM-DD. Entered dates are not coverage determinations.
Six months, with the first month included
The federal planning window uses the first month in which you are 65 or older and enrolled in Part B. This calculator uses the later of your age-65 birth month and Part B effective month, then includes that month plus five more months. It assumes continuous Part B enrollment. First-of-month birthday adjustments from the IEP calculator are not automatically applied to Medigap age qualification; confirm your actual window with Medicare.
Example: you turn 65 in May 2027 and Part B starts May 2027: May 1 through October 31. If Part B starts September, the estimated window runs September 1 through February 29, 2028.
State exceptions and additional protections may apply, including protections for some people under 65. Other guaranteed-issue rights are separate. Outside applicable protections, underwriting or refusal may be possible. Annual Medicare Open Enrollment does not establish a Medigap acceptance guarantee. Confirm with your state insurance department and Medicare.
Official sources
Planning reference as of Oct 11, 2026. Source URLs are from the local SEO plan; offline build, no live-source verification.